Increased urinary concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and their metabolites are associated with increased risk of unexplained infertility in males. The toxicity of PAHs and dioxins are exclusively mediated through Aryl hydrocarbon Receptor (AhR). AhR overexpression contributes to the loss of normal ovarian function in polluted environments but its expression level in unexp...

In humans, as in all mammalian males, Leydig cells are the main source of the androgenic hormone, testosterone, which is essential for male sexual differentiation, gamete production and maturation, and development of secondary sexual characteristics. In this chapter, the development, steroidogenic function, and regulation of human Leydig cells are summarized. Clinical aspects of androgen secret...

The influence of prolactin (PRL) and corticosterone on insulin binding to purified rat Leydig cells was assessed in vitro. The lowest dose of PRL (50 ng/ml) increased (p<0.05) and the remaining PRL concentrations (100, 150, 200, 250 ng/ml) decreased (p<0.05) the insulin binding to Leydig cells. All doses of corticosterone (150, 200, 250, 300 ng/ml) except the lowest one (100 ng/ml) decreased th...

The physiological role of multidrug resistance protein 4 (Mrp4, Abcc4) in the testes is unknown. We found that Mrp4 is expressed primarily in mouse and human Leydig cells; however, there is no current evidence that Mrp4 regulates testosterone production. We investigated its role in Leydig cells, where testosterone production is regulated by cAMP, an intracellular messenger formed when the lutei...

Adult Leydig cells (ALCs) are the steroidogenic cells in the testes that produce testosterone. ALCs develop postnatally from a pool of stem cells, referred to as stem Leydig cells (SLCs). SLCs are spindle-shaped cells that lack steroidogenic cell markers, including luteinizing hormone (LH) receptor and 3β-hydroxysteroid dehydrogenase. The commitment of SLCs into the progenitor Leydig cells (PLC...

testosterone is believed to play a significant role in spermatogenesis, but its contribution to the process of spermatogenesis is not completely understood. given that extracellular matrix (ecm) facilitates differentiation of spermatogonial stem cells (sscs) during culture, the present study was conducted to elucidate whether testosterone contribute to the permissive effect of ecm on sscs diffe...

Transforming growth factor β1 (TGF-β1) is a polypeptide with various biological activities. Recent studies have shown that this and they receptors are expressed in human Leydig cells, Sertoli spermatogonia, spermatocytes sperm cells after birth, involved the endocrine regulation of spermatogenesis. However, there no report on expression TGF-β embryonic testis. TGF-β1 peptide widely distributed ...

The effects of luteinizing hormone (LH) and human chorionic gonadotrophic hormone (hCG) on Leydig cell structure and function are reviewed in this paper under two main headings; responses to LH and hCG stimulation and responses to LH deprivation. With acute LH stimulation, up to 2 hours following the LH injection, there was no change in the volume of a Leydig cell. However, Leydig cell peroxiso...

In the present study, we investigated the effects of oral dosing of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) to peripubertal male rats (50 and 200 mg/kg body weight daily from postnatal days 23-50) on ex vivo Leydig cell steroidogenesis. Leydig cells from treated rats were characterised by significant decline in mRNA transcripts of several genes responsible for steroidogenes...